Frequency-modulated continuous-wave radar signals (FMCW signals) are used in many currently available radar sensors, for example, in the case of near-distance-sensing devices in the automotive sector. By means of the FMCW principle, it is possible to make a targeted statement about the distance and relative velocity of an object relative to the radar sensor. In this context, a frequency-modulated form of a continuously transmitted signal is used, wherein the individual signal portions, so-called chirps, are conventionally intermittently linear, but can provide different gradients, so-called chirp rates. The chirps can also occur in pulsed form. In this context, several chirps, for example, 128, are transmitted per period in a sequence with a subsequent resting time.
The typical signal shape in this context satisfies the following description:
                                          FMCW            ⁡                          (              t              )                                =                                    ∑                              n                =                1                            N                        ⁢                                          (                                                                                                    (                                                                                                            f                              n                                                        -                                                          f                                                              n                                -                                1                                                                                                                                          T                            n                                                                          )                                                                    ︸                        Chirprate                                                              ·                                          (                                              t                        -                                                  t                          n                                                                    )                                                        +                                      f                                          n                      -                      1                                                                      )                            ·                              g                ⁡                                  (                                                            t                      -                                              t                        n                                                              ;                                          T                      n                                                        )                                                                    ,                                  ⁢                              for            ⁢                                                  ⁢            t                    ⁢                                          ∈                      (                                          t                0                            ,                              t                N                                      )                                              (        1.1        )            where:
N is the number of linear segments per signal period
Tn is the time interval with constant chirp rate
fn is the frequency offset at the end of a linear segment
FMCW(t)=FM(t−P), with the signal period P =tn−t0 
g(t; T) is the window function which takes the value 1 for t ϵ (t0, tN) and is otherwise 0,
t is time
n is the counting index
Analyzing these FMCW signals with regard to their key properties represents a substantial point in the development of current and future radar systems. Accordingly, the uniqueness range is determined by the chirp duration, the resolution is determined by the chirp rate, and the measurement accuracy is determined by the linearity of the chirps. These signal properties represents a central component of the overall system and must therefore be known as well as possible. However, it has not yet been possible to provide automation for the automatic detection and evaluation of FMCW signals. The analysis of the characteristic FMCW signal is currently effort-intensive, because the significant parameters of the FMCW signal must be determined individually. This is complicated and susceptible to error, especially in the case of a poor signal-noise ratio.
EP 0 667 536 A2 shows a conventional method for measuring FMCW signals by way of example. With the use of the method shown there, considerable technical knowledge is required of the user. Even if such a considerable technical knowledge is available, an optimal measurement result can be achieved only with considerable effort.
What is needed, therefore, are approaches for a measuring device and measuring method for performing measurement of FMCW signals, and at the same time require only minimal technical knowledge on the part of the user and a minimal operating effort.